System for production of ethanol and co-products with raw starch hydrolysis and solvent washing of fermentation product

ABSTRACT

A system for the production of ethanol and co-products is provided. The system facilitates an overall reduction in the use of energy, for example, by reducing the mass of wet solids supplied to a distillation system. The system also reduces the amount of energy used to dry the wet solids component of a fermentation product, for example, by increasing the ethanol concentration of the wet solids. The system also facilitates the recovery of co-products including bioproducts and other biochemicals extracted from components of the fermentation product. The solids component of the fermentation product may be dried and constituted into a meal that may be used for animal feed, among other uses.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority from and the benefit of andincorporates by reference, each of the following: (a) U.S. ProvisionalApplication Ser. No. 61/140,454, entitled FORMING DRIED SOLID FROM AFERMENTATION PROCESS, filed Dec. 23, 2008; (b) U.S. ProvisionalApplication Ser. No. 61/161,342, entitled PROCESS FOR LOW ENERGY DRYINGOF ETHANOL FERMENTATION SOLIDS, filed Mar. 18, 2009; (c) U.S.Provisional Application Ser. No. 61/161,622, entitled PROCESS FOR LOWENERGY DRYING OF ETHANOL FERMENTATION SOLIDS, filed Mar. 19, 2009; (d)U.S. Provisional Application Ser. No. 61/161,684, entitled LOW ENERGYDRYING OF ETHANOL FERMENTATION SOLIDS WITH REDUCTION OF NON-FERMENTABLEINPUTS, filed Mar. 19, 2009; (e) U.S. Provisional Application Ser. No.61/162,097, entitled LOW ENERGY DRYING OF ETHANOL FERMENTATION SOLIDSWITH MULTIPLE ETHANOL FEEDS, filed Mar. 20, 2009; (f) U.S. ProvisionalApplication Ser. No. 61/168,331, entitled PROCESS FOR PRODUCING ETHANOL,filed Apr. 10, 2009; (g) U.S. Provisional Application Ser. No.61/179,347, entitled PROCESS FOR PRODUCING ETHANOL, filed May 18, 2009;and (h) U.S. Provisional Application Ser. No. 61/179,348, entitledPROCESS FOR PRODUCING ETHANOL, filed May 18, 2009.

BACKGROUND

Ethanol can be produced from grain-based feedstocks (such as corn),cellulosic feedstocks (such as switchgrass or corn cobs), or other plantmaterial (such as sugar cane).

In a conventional ethanol plant producing ethanol from corn, cornkernels are processed to separate the starch-containing material (e.g.endosperm) from other matter (such as fiber and germ). Thestarch-containing material is then slurried with water and liquefied tofacilitate saccharification where the starch is converted into sugar(i.e. glucose) and fermentation where the sugar is converted by anethanologen (i.e. yeast) into ethanol. The product of fermentation isbeer, which comprises a liquid component containing ethanol and water(among other things) and a solids component containing unfermentedparticulate matter (among other things).

According to the process typically used at a conventional ethanol plant,the liquefaction of the starch-containing material is done by “cooking”the slurry at temperature at or near boiling point of water. Accordingto an alternative process (that has been developed and implemented bythe assignee of the present application), for example, as described inU.S. Patent Application Publication No. 2005/0239181, raw starch may beconverted and fermented without “cooking” or liquefication.

In a conventional ethanol plant, the liquid component and solidscomponent of the fermentation product is sent to a distillation system.In distillation, the fermentation product is processed into, among otherthings, ethanol and stillage containing wet solids (i.e. the solidscomponent of the beer with substantially all ethanol removed) formedinto a wet cake which can be dried into distillers dried grains (DDG)and sold as an animal feed product. Other co-products, for example,syrup (and oil contained in the syrup) can also be recovered from thestillage. Water removed from the fermentation product in distillationcan be treated for re-use at the plant.

In a conventional ethanol plant, certain plant operations are conductedat elevated temperatures over ambient temperature with the resultantconsumption of energy. For example, the liquefaction of thestarch-containing slurry is typically done with a jet cooker (usingnatural gas as a fuel to elevate the temperature of the slurry to aboil). The amount of energy used in the distillation process (anotheroperation performed at an elevated temperature, with heat typicallyprovided by steam from an on-site boiler) is a function, among otherthings, the volume/mass of material supplied to the distillation system.And the drying of wet solids into distillers dried grains, an operationin which water is removed from the solids typically in a dryer (such asa ring dryer) heated by natural gas, will consume energy as a functionof the properties (e.g. heat capacity, heat of vaporization and boilingpoint) of the water to be removed from the solids.

It would be advantageous provide for a system for producing ethanol thatfacilitates an overall reduction in the use of energy at the plant, forexample, by reducing the mass of wet solids supplied to the distillationsystem. It would also be advantageous to provide for a system forproducing ethanol that reduced the amount of energy used to dry the wetsolids component of the fermentation product. It would further beadvantageous to provide for a system for producing ethanol thatfacilitated the recovery of co-products including bioproducts and otherbiochemicals extracted from components of the fermentation product. Itwould further be advantageous to provide for a system for producingethanol in which the solids component of the fermentation product wouldbe dried and constituted into a meal that could be used for animal feed,among other uses.

SUMMARY

The present invention relates to a system and method for processing afermentation product of a fermentation process in a biorefinery thatperforms distillation of ethanol, the fermentation product comprising aliquid component and a solids component, the method comprising the stepsof: (a) preparing a corn feedstock into a slurry containing fermentablematter, (b) saccharifying and fermenting the slurry while maintainingthe slurry at a temperature below a starch gelatinization temperature toobtain a fermentation product, the fermentation product comprising aliquid component and a solids component, (c) applying a solvent to thesolids component, and (d) drying the solids component.

DRAWINGS

FIG. 1 is a process flow diagram of an exemplary embodiment of abiorefinery.

FIG. 2 is a process flow diagram of an exemplary embodiment of thebiorefinery of FIG. 1.

FIG. 3 is a process flow diagram of an exemplary embodiment of thebiorefinery of FIG. 1.

FIG. 4 is a process flow diagram of an exemplary embodiment of thebiorefinery of FIG. 1.

FIG. 5 is a process flow diagram of an exemplary embodiment of thebiorefinery of FIG. 1.

FIG. 6 is a block flow diagram of an exemplary embodiment of thebiorefinery.

FIG. 7 is a block flow diagram of an exemplary embodiment of thebiorefinery.

FIG. 8 is a block flow diagram of an exemplary embodiment of thebiorefinery.

FIG. 9 is a block flow diagram of an exemplary embodiment of thebiorefinery.

FIG. 10 is a block flow diagram of an exemplary embodiment of thebiorefinery.

FIG. 11 is a block flow diagram of an exemplary embodiment of thebiorefinery.

FIG. 12 is a block flow diagram of an exemplary embodiment of thebiorefinery.

FIG. 13 is a block flow diagram of an exemplary embodiment of solidswashing processes.

FIG. 14 is a process flow diagram of an exemplary embodiment of thesolids washing processes.

FIG. 15 is an exemplary graphical representation of energy for dryingwet solids vs. the ethanol concentration of the wet solids.

FIG. 16 is a block flow diagram of an exemplary embodiment of the solidswashing processes.

FIG. 17 is a process flow diagram of an exemplary embodiment of thesolids washing processes.

FIGS. 18A and 18B are cross-sectional views of an exemplary embodimentof a wash process capable of implementing multiple wash stages.

FIGS. 19 through 23 are cross-sectional views at various locations alongthe filter belt of FIGS. 18A and 18B.

FIG. 24 is a perspective view of an exemplary embodiment of the ethanolwash process.

FIG. 25 is a flow chart of the exemplary embodiment of the solidswashing processes.

FIG. 26 is a flow chart of the exemplary embodiment of multiple solidswashing processes.

FIG. 27 is a process flow diagram of an exemplary embodiment of thefractionation process.

FIG. 28 is a block flow diagram of an exemplary embodiment of thesaccharification process.

FIG. 29 is a block flow diagram of an exemplary embodiment of thefermentation process.

FIG. 30 illustrates exemplary embodiments of the separation process.

DETAILED DESCRIPTION

FIG. 1 is a process flow diagram of an exemplary embodiment of abiorefinery 10. Biorefinery 10 receives a feedstock, illustrated as corn12, and processes the feedstock to produce several usable products forconsumption, principally ethanol. Although illustrated as corn 12, othertypes of feedstock such as sorghum, wheat, barley, potatoes, sugar cane,switchgrass, and corn cobs, may be processed by biorefinery 10.Additional inputs such as enzymes, yeast, water, and energy (e.g., heatenergy) may be added to the feedstock to facilitate production of theusable products. The usable products from biorefinery 10 may includebioproducts 14, such as corn oil, corn syrup, bran, flour, proteins(e.g., zein), and other suitable bioproducts, ethanol 16, and an animalfeed 18 shown as distillers dried grain (DDG).

Ethanol 16 is an alcohol produced from corn 12 or other starch-basedcrop. Ethanol 16 has many uses, and of particular interest is itscapacity to be blended with gasoline for use in motor vehicles 20.Ethanol 16 is a relatively clean-burning, high-octane fuel that may beproduced domestically in the United States from renewable sources,reducing the dependence on foreign sources of energy. Ethanol 16 alsodelivers economic vitality to agricultural regions where the feedstocksare produced. Ethanol blends increase fuel octane ratings, decreaseharmful fossil fuel emissions, reduce fuel costs, and extend the overallsupply of gasoline.

FIG. 2 is a process flow diagram of an exemplary embodiment ofbiorefinery 10 of FIG. 1. Corn 12 may be directed into apreparation/fractionation process 24, where corn kernels of corn 12 maybe separated into non-fermentable solids (e.g., germ and fiber) andfermentable solids (e.g., endosperm). Once the endosperm has beenseparated from the non-fermentable solids, the endosperm may be groundinto ground endosperm, which may be directed into a saccharificationprocess 26. Separation and grinding of endosperm may also be conductedin an integrated process. Saccharification process 26 may also receiveadditional inputs (e.g., heat, water, and enzymes) and may convertstarches within the ground endosperm into sugars, which may be suitablefor fermenting. A fermentation slurry may be directed fromsaccharification process 26 into a fermentation process 28.

Fermentation process 28 may also receive additional inputs (e.g., yeastand enzymes) and may ferment the sugars within the fermentation slurryto produce a certain concentration of ethanol within the fermentationslurry. Fermentation process 28 may produce a certain amount of carbondioxide (CO₂) and other gases, which may be processed through the use ofa scrubber 30 or other suitable equipment. The main product offermentation process 28 is a fermentation product shown as beer 32comprises a liquid component and a solids component and is generally amixture of ethanol, water, syrup, particulate matter, and dissolvedsolids. Saccharification process 26 and fermentation process 28 may beperformed separately, or according to certain embodiments, may becombined into a substantially integrated process (e.g., calledsimultaneous saccharification and fermentation (SSF)).

Beer 32 may be directed into solids processing system 34, which may washbeer 32 with ethanol (or other solvent). Solids processing system 34 ofFIG. 2 include a separation/wash process 36, a separation process 38,and a desolventizing process 40. Beer 32 may be separated into a liquidcomponent and a solids component by separation/wash process 36. Theliquid component from separation/wash process 36 may be processed by aseries of distillation system 42, which primarily produce ethanol 16.Distillation system 42 may include a distillation pre-treatment process44, a distillation process 46, and a dehydration/filtration process 48.Distillation pre-treatment process 44 may remove wet solids componentsfrom the liquid component before distillation process 46 producesethanol, which may be dried within dehydration/filtration process 48 toremove any remaining water 49. Dehydration/filtration process 48 mayinclude any suitable type of dehydration, such as dessication. Water 49removed from distillation system 42 may be used as make-up water, as aslurry water source, or as a source of water for other processesinternal or external to biorefinery 10.

The solids component comprises ethanol, water, syrup, meal, zein,lutein, lysine, various proteins (having different attributes andnutritional values), yeast, fiber, and other particulate matter anddissolved solids. The solids component may be processed through solidsprocessing system 34, which primarily produces meal 18 and severalbiochemicals, such as zein and xanthophylls. Ethanol 16 fromdistillation process 46 and/or dehydration/filtration process 48 may beused in separation/wash process 36 to wash the solids component withethanol, increasing the ethanol concentration of the solids componentand reducing the energy required to desolventize the solids component inthe desolventizing process 40 to produce meal 18. Liquids removed byseparation process 38 and desolventizing process 40 may be directed toseparation/wash process 36.

FIG. 3 is a process flow diagram of an exemplary embodiment ofbiorefinery 10 of FIG. 1. The processes are substantially similar tothose of FIG. 2 through the production of beer 32. Beer 32 may bedirected into a separation process 50, which separates the beer 32 intoa liquid component and a solids component. The liquid component fromseparation process 50 may be processed by distillation processesoperating through distillation system 42 to produce ethanol 16.

The solids component may be directed into a wash process 52, whichwashes the solids component with ethanol 16 from distillation process 46and/or dehydration/filtration process 48. Biochemicals removed by washprocess 52 may be extracted by a biochemical extraction process. Certaincomponents from wash process 52 may be directed into distillation system42 (e.g., distillation pre-treatment process 44). Ethanol-washed solidsfrom wash process 52 may be directed into separation process 38, where acertain amount of water and ethanol may be removed before the ethanol(e.g., solvent) is removed by desolventizing process 40 to produce meal18. Liquids removed by separation process 38 and desolventizing process40 may be directed to wash process 52.

FIG. 4 is a process flow diagram of an exemplary embodiment ofbiorefinery 10 of FIG. 1. The processes are substantially similar tothose of FIGS. 2 and 3 through the production of beer 32. Beer 32 may bedirected into distillation process 46, with ethanol from distillationprocess 46 being directed to dehydration/filtration process 48, and theliquid/solids mixture (e.g., stillage) from distillation process 46being directed into separation/wash process 36. Separation/wash process36 may receive ethanol from distillation process 46 and/ordehydration/filtration process 48 and wash the liquid/solids mixture(e.g., stillage) from distillation process 46 with the ethanol,increasing the ethanol concentration of the liquid/solids mixture (e.g.,stillage). The ethanol-washed liquid/solids mixture (e.g., stillage) maybe directed into separation process 38, where a certain amount of waterand ethanol may be removed before the ethanol (e.g., solvent) is removedby desolventizing process 40 to produce distillers dried grain (DDG) 54.Liquids removed by separation process 38 and desolventizing process 40may be re-cycled back through separation/wash process 36. Biochemicalsand stillage may be extracted from separation/wash process 36.

FIG. 5 is a process flow diagram of an exemplary embodiment ofbiorefinery 10 of FIG. 1. The processes are substantially similar tothose of FIGS. 2 through 4 through the production of beer 32. Beer 32may be directed into wash process 52, which may wash beer 32 withethanol from distillation process 46 and/or dehydration/filtrationprocess 48. The ethanol-washed beer 32 may be directed into separationprocess 38, where a certain amount of water and ethanol may be removedbefore the ethanol (e.g., solvent) is removed by desolventizing process40 to produce meal 18. Liquid removed by separation process 38 anddesolventizing process 40 may be re-cycled back through wash process 52.Ethanol and water from wash process 52, separation process 38, anddesolventizing process 40 may also be directed into distillation system42 (e.g., distillation pre-treatment process 44).

FIG. 6 is a block flow diagram of an exemplary embodiment of biorefinery10. Corn 12 may first be directed into preparation/fractionation process24, where it is prepared for saccharification and fermentation.Non-fermentable solids in corn 12 may be separated (e.g., fractionated)from fermentable solids. Corn kernels generally comprise endosperm,germ, and fiber. Endosperm comprises most of the starches and proteinsavailable in a corn kernel and, therefore, is used in fermentationprocess 28 to generate ethanol. In other words, endosperm represents thefermentable solids of a corn kernel; germ and fiber represent thenon-fermentable solids, which may be withheld from fermentation process28. Endosperm comprises approximately 80-85% of a corn kernel, germcomprises approximately 10-15% of a corn kernel, and fiber comprisesapproximately 5-10% of a corn kernel, all by mass.

Non-fermentable solids 56 may be directed into various bioproductprocesses, which may produce usable bioproducts 14. Non-fermentablesolids 56 may include the germ and fiber of corn 12, which may beprocessed into bioproducts such as corn oil, corn syrup, bran, flour,and proteins (e.g., zein). Fermentable solids 58 (e.g., endosperm ofcorn 12) from preparation/fractionation process 24 may be directed intoa saccharification/fermentation process 60, which may includesaccharification process 26 and fermentation process 28.Saccharification process 26 and fermentation process 28 may be conductedseparately (e.g., in separate stages) or may be conducted concurrently(e.g., in an integrated stage). It should be noted that fermentablesolids 58 may contain small portions of non-fermentable components(e.g., germ and fiber) not intended for the fermentation process.

Preparation/fractionation process 24 may include passing corn 12 throughmills, such as hammer mills and pins mills, to grind fermentable solids58 into a fine powder (e.g., flour), further facilitatingsaccharification/fermentation process 60. Fermentable solids 58 (e.g.,endosperm) include a high proportion of starches suitable for fermentingto produce ethanol 16. Saccharification/fermentation process 60 mayinclude saccharifying fermentable solids 58 to convert the starcheswithin fermentable solids 58 into sugars. The process of saccharifyingfermentable solids 58 may include adding heat, water, and enzymes tofermentable solids 58 to produce a fermentation slurry.

Saccharification/fermentation process 60 may also include adding yeastto the fermentation slurry. The yeast helps convert the sugars withinthe fermentation slurry into ethanol 16 and carbon dioxide. Thefermentation slurry may be agitated and cooled until the concentrationof ethanol 16 has been maximized. The output fromsaccharification/fermentation process 60 may be referred to asfermentation product 32, which may generally include ethanol 16, but mayalso include a certain amount of water, as well as syrup, particulatematter, and dissolved solids.

Fermentation product may be separated by separation process 50 into aliquid component and a solids component, both of which may be processedin respective processing paths. The liquid component may include liquid62, which contains ethanol 16, a certain amount of water and othernon-ethanol liquids, as well as fine solids, which may be removed fromliquid 62. Distillation system 42 may remove most of the water, othernon-ethanol liquids, and fine solids to produce ethanol 16. Ethanol 16leaving distillation system 42 may contain various target concentrationsof ethanol, such as from approximately 95% (e.g., 190 proof) toapproximately 100% (e.g., 200 proof). Stillage 66 (e.g., comprisingliquid and wet solids) from distillation system 42 may be processedand/or combined into bioproducts 14 (e.g., animal feed, oils, syrup, andother biochemicals).

The solids component may include wet solids 64, which may include acertain amount of ethanol, a certain amount of water, syrup, particulatematter, and dissolved solids. It should be noted that when reference ismade to “solids,” the solids may include particulate matter anddissolved solids, which may be associated with a certain amount ofliquids (e.g., “wet solids”). Solids processing system 34 anddesolventizing process 40 may remove most of the water and ethanol fromwet solids 64 to produce meal 18. Solids processing system 34 mayinclude washing wet solids 64 with ethanol or a liquid with a desiredethanol content to decrease the boiling point, specific heat, andenthalpy (heat) of vaporization of the wet solids 64, reducing theenergy required to dry (e.g., desolventize) wet solids 64 to producemeal 18. The ethanol may be directed to solids processing system 34.

FIG. 7 is a block flow diagram of an exemplary embodiment of biorefinery10. The processes are substantially similar to those of FIG. 6 throughthe production of beer 32. The fermentation product shown as beer 32 maybe directed into distillation system 42, where beer 32 is distilled toproduce ethanol 16. Stillage 66 from distillation system 42 may bedirected into solids processing system 34 (e.g., including separationand washing), where stillage 66 may be washed with ethanol fromdistillation system 42 and/or desolventizing process 40 to increase theethanol concentration of stillage 66, reducing the amount of energyrequired by desolventizing process 40 to remove liquids from stillage 66to produce DDG 54. Thin stillage may be removed from solids processingsystem 34 as bioproducts 14.

FIG. 8 is a block flow diagram of an exemplary embodiment of biorefinery10. The processes are substantially similar to those of FIGS. 6 and 7through the production of the fermentation product shown as beer 32.Beer 32 may be separated by separation process 50 into a liquidcomponent shown as comprising liquid 62 and a solids component shown ascomprising wet solids 64. Ethanol 16 may be recovered from liquid 62 bydistillation system 42; wet solids 64 may be directed into solidsprocessing system 34, where solids may be washed with a solvent 68(e.g., hexane) other than ethanol. Solvent 68 may be received by solidsprocessing system 34 from a solvent conditioning process 70, which mayin turn receive spent solvent from solids processing system 34, forminga closed-loop cycle of solvent 68 through solids processing system 34.Solvent from solvent-washed wet solids 64 may be removed bydesolventizing process 40 to produce meal 18. Solvent conditioningprocess 70 may also remove a ethanol/water mixture 71 and direct theethanol/water mixture 71 to distillation system 42. Solvent conditioningprocess 70 may further remove water 72 and extracted co-products 74 fromwet solids 64.

FIG. 9 is a block flow diagram of an exemplary embodiment of biorefinery10. The processes are substantially similar to those of FIGS. 6 through8 through the production of the fermentation product shown as beer 32.Beer 32 may be directed into distillation system 42, where beer 32 isdistilled to produce ethanol 16. Stillage 66 from distillation system 42may be directed into solids processing system 34 (e.g., separation andwashing), where stillage 66 may be washed with solvent 68 (e.g.,hexane). Solvent 68 may be received by solids processing system 34 fromsolvent conditioning process 70, which may in turn receive spent solventfrom solids processing system 34, forming a closed-loop cycle of solvent68 through solids processing system 34. Solvent from solvent-washed wetsolids 64 may be removed by desolventizing process 40 to produce DDG 54.Solvent conditioning process 70 may further remove water 72 andextracted co-products 74 from stillage 66. Thin stillage may be removedfrom solids processing system 34 as bioproducts 14.

FIG. 10 is a block flow diagram of an exemplary embodiment ofbiorefinery 10. Biorefinery 10 begins with preparation/fractionationprocess 24, which may include a preparation process 76 and/or afractionation process 78. Preparation/fractionation process 24 preparescorn 12 for saccharification and fermentation in saccharificationprocess 26 and fermentation process 28.

Preparation process 76 may include a cleaning stage to remove impuritiesthat may be present in the corn, such as stalks, cobs, stone, sand, andother fine particles. Clean corn output from the cleaning stage may bedirected into a water tempering stage, where corn 12 may be temperedwith a water concentration for a period of time. In the water temperingstage, the water penetrates the germ and fiber of corn 12, facilitatingsubsequent removal of the germ and fiber from corn 12, as well asincreasing resistance of the germ and fiber to physical breakage duringsubsequent stages (e.g., further separation).

Tempered whole corn 12 from preparation process 76 may then be directedinto fractionation process 78. Corn 12 may be fractionated intonon-fermentable solids 56 (e.g., primarily germ and fiber) andfermentable solids 58 (e.g., primarily endosperm) with fermentablesolids 58 being milled to reduce the particle size of fermentable solids58. The downstream processes of biorefinery 10 may not require that corn12 be fractionated into endosperm, germ, and fiber. For example,separation process 50 and solids processing system 34 do not requirefractionated corn 12 to lead to beneficial results, although suchfractionation may enhance the benefits.

The ground endosperm from fractionation process 78 may be directed intosaccharification process 26, in which starch within the endosperm may beconverted into sugars that can be fermented by a microorganism, such asyeast. The conversion may be accomplished by saccharifying the endospermwith a number of additional inputs, such as saccharifying enzymecompositions, without cooking the endosperm. The downstream processes ofbiorefinery 10 may not require that corn 12 be saccharified prior tofermentation process 28, although certain benefits and co-products maybe enhanced by saccharification process 26.

The output of saccharification process 26 may be described as afermentation slurry, which may be directed into fermentation process 28,in which sugars within the fermentation slurry are fermented to produceethanol 16. Additional inputs (e.g., microorganisms such as yeast) maybe introduced into fermentation process 28 to facilitate the fermenting.The output of fermentation process 28 may include fermentation product32, such as a mixture of ethanol, water, syrup, particulate matter(e.g., fiber, germ, yeast, etc.), and dissolved solids.

Fermentation product 32 from fermentation process 28 may be directedinto separation process 50, in which fermentation product 32 isseparated into a liquid component (e.g., liquid 62) and a solidscomponent (e.g., wet solids 64). The equipment used for separationprocess 50 may vary and may include, for example, centrifuges,decanters, hydroclones, sedimentation tanks, and filter presses.

Liquid 62 (e.g., water/ethanol mixture) and wet solids 64 (e.g., wetsolids) may then be directed into separate processing paths. Liquid 62may be directed into distillation system 42; wet solids 64 may beprocessed through solids processing system 34. An end product of theliquids processing path is ethanol 16; an end product of the solidsprocessing path is meal 18 (and possibly other bioproducts such asbiochemicals).

Liquid 62 (e.g., water/ethanol mixture) from separation process 50 mayfirst be directed into distillation pre-treatment process 44, in whichliquid 62 is prepared for further distillation. Distillationpre-treatment process 44 may include heating liquid 62 prior todistillation. Distillation pre-treatment process 44 may also includeremoving the remaining fractions of germ and fiber from liquid 62 asbioproducts 14. Once liquid 62 has been pre-treated by distillationpre-treatment process 44, the pre-treated liquid 62 may be directed intodistillation process 46, in which water may be removed from ethanol 16.Ethanol 16 from distillation process 46 may be approximately 190 proof(e.g., approximately 95% alcohol). Ethanol 16 from distillation process46 may then be directed into dehydration/filtration process 48, in whichethanol 16 is further dried and filtered. Ethanol 16 fromdehydration/filtration process 48 may be approximately 200 proof (e.g.,approximately 100% alcohol). Ethanol 16 from dehydration/filtrationprocess 48 may be sold for use as a fuel.

Wet solids 64 from separation process 50 may first be directed into awash process 52, in which wet solids 64 are washed with variousconcentrations of ethanol 16 to increase the ethanol concentration ofwet solids 64. The wet solids 64 may then be directed into separationprocess 38 and desolventizing process 40, in which the wet solids 64 maybe deliquified, separated, and desolventized to generate meal 18. Byincreasing the ethanol concentration of wet solids 64 in wash process52, the boiling point of the liquid component of the wet solids will bedecreased, as will its specific heat and enthalpy (heat) ofvaporization, reducing the energy required to dry (e.g., desolventize)the wet solids in desolventizing process 40. Wash process 52 andseparation process 38 may be integrated or separate, such that eachstage through wash process 52 and separation process 38 progressivelyincreases the ethanol content in the wet solids. Ethanol 16 fromseparation process 38 and desolventizing process 40 may be used toincrease the ethanol concentration of wet solids 64 in wash process 52.

FIG. 11 is a block flow diagram of an exemplary embodiment ofbiorefinery 10. The processes are substantially similar to those of FIG.10 through fermentation process 28. Fermentation product 32 fromfermentation process 28 may be directed into distillation system 42(e.g., distillation pre-treatment process 44, distillation process 46,and dehydration/filtration process 48), where fermentation product 32 isdistilled to produce ethanol 16. Stillage 66 from distillation process46 may be directed into solids processing system 34, where stillage 66may be washed with ethanol to increase the ethanol concentration ofstillage 66, reducing the amount of energy required by desolventizingprocess 40 to remove liquids from stillage 66 to produce DDG 54. Solidsprocessing system 34 may receive the ethanol from distillation process46 and/or dehydration/filtration process 48. A certain amount of ethanolfrom desolventizing process 40 may be directed back to solids processingsystem 34 for further use. An extraction process 79 may also extractbioproducts 14 from solids processing system 34. Some biochemicals maybe extracted from solids processing system 34 and directed intodistillation pre-treatment 44 for further processing.

FIG. 12 is a block flow diagram of an exemplary embodiment ofbiorefinery 10. The processes are substantially similar to those ofFIGS. 10 and 11 through fermentation process 28. Fermentation product 32from fermentation process 28 may be separated by separation process 50into a liquid component shown as comprising liquid 62 and a solidscomponent shown as comprising wet solids 64. Liquid 62 may be convertedinto ethanol 16 by distillation system 42 (e.g., distillationpre-treatment process 44, distillation process 46, anddehydration/filtration process 48); wet solids 64 may be directed intowash process 52, where solids may be washed with a solvent 68 (e.g.,hexane) other than ethanol. Solvent 68 may be received by wash process52 from solvent conditioning process 70, which may in turn receive spentsolvent from wash process 52, forming a closed-loop cycle of solvent 68through wash process 52. Solvent from solvent-washed wet solids 64 maybe removed by separation process 38 and desolventizing process 40 toproduce meal 18. Some of the solvent removed from separation process 38and desolventizing process 40 may be directed to wash process 52 forfurther use. Solvent conditioning process 70 may also remove anethanol/water mixture 71 and direct the ethanol/water mixture 71 todistillation system 42 (e.g., distillation pre-treatment process 44).Solvent conditioning process 70 may further remove water 72; extractionprocess 79 may extract co-products 74. Both pre-treatment process 44 andwash process 52 may facilitate the recovery of bioproducts 14 availablefrom the fermentation product 32.

The individual processes of biorefinery 10 may be highly synergistic,with each process contributing to efficiencies and other benefits ofother processes. For example, by fractionating and milling the feedstockinto primarily ground endosperm in fractionation process 78, thedownstream processes of biorefinery 10 may be indirectly enhanced.Because primarily fermentable endosperm is directed intosaccharification process 26, only enough energy to saccharify theendosperm will be required by saccharification process 26. Energy neednot be expended processing the non-fermentable solids (e.g., germ andfiber) in saccharification process 26 or in other processes, such as theoperation of distillation system 42. Because the fermentation slurryfrom saccharification process 26 consists of primarily fermentablesolids, water, and enzymes, fermentation process 28 may also begenerally more efficient.

By saccharifying the ground endosperm in saccharification process 26without cooking, the amount of heat input into the ground endosperm maybe lower as compared to conventional cooking processes. Saccharifyingthe ground endosperm without “cooking” (e.g., using “raw starch”hydrolysis) may lead to meal 18 having a different quality than DDG 54produced by conventional biorefineries. For example, meal 18 may behigher in protein values, as well as higher in amino acids (e.g.,lysine) and other biochemicals having different attributes andqualities, than typical DDG 54.

Separating a liquid component comprising liquid 62 from a solidscomponent comprising wet solids 64 in separation process 50 may lead toseveral benefits downstream of separation process 50. Because wet solids64 (e.g., a certain amount of ethanol, a certain amount of water, syrup,particulate matter, and dissolved solids) have been substantiallyremoved from liquid 62 (e.g., a water/ethanol mixture), the distillationequipment of distillation process 46 will be much less likely toencounter fouling from wet solids 64, which may otherwise impair theperformance of the distillation equipment, render it less efficient,and/or require cleaning. The distillation equipment of distillationprocess 46 may also be sized smaller because the added mass of wetsolids 64 need not be processed through the distillation equipment. Theremoval of wet solids 64 may also lead to the distillation equipment ofdistillation process 46 requiring less energy than conventionaldistillation equipment.

The combination of the processes of biorefinery 10 may lead to overallenergy reduction of biorefinery 10, as well as reducing the temperatureto which the products of biorefinery 10 are exposed. Wet solids 64,stillage 66, meal 18, and DDG 54 may all be processed by biorefinery 10without ever experiencing temperatures above approximately 150° C.Maintaining the temperature below 150° C. has been shown to reduce thepossibility of degradation of the resulting meal 18 or DDG 54. Reduceddegradation may include color transformation and significant oxidationof residual starches downstream of fermentation process 28. Usingmeasurements of the resulting meal 18 or DDG 54, such as neutraldetergent fiber (NDF) measurements, it has been found that maintainingthe temperatures experienced by meal 18 or DDG 54 within biorefinery 10under approximately 150° C. significantly reduces the possibility ofdegrading the resultant meal 18 or DDG 54. Using these samemeasurements, it has been found that maintaining the temperaturesexperienced by meal 18 or DDG 54 within biorefinery 10 underapproximately 100° C. may further reduce the possibility of degradingthe meal 18 or DDG 54.

FIGS. 13 and 14 are a block flow diagram and a process flow diagram ofan exemplary embodiment of solids processing system 34. Wet solidscomponents 80 (e.g., wet solids 64 or stillage 66) may be washed withethanol 16 to increase the ethanol concentration, facilitating thereduction of energy required for drying. Wet solids components 80 maygenerally comprise wet solids or wet beer solids. Washing with ethanolmay lead to lower drying energy consumption regardless of whether aliquid component (e.g., liquid 62) and a solids component (e.g., wetsolids 64) have been separated by separation process 50. The ethanolwash may also be used with wet solids exiting a distillation process, asin existing plants.

A stream of ethanol 16 may be introduced into wet solids components 80.The stream of ethanol 16 may be received from distillation system 42 ormay be received from other sources internal or external to biorefinery10. The stream of ethanol 16 may be fed through ethanol feed flow lines82 into an ethanol distribution system 84, which applies (e.g., sprays,mists, drips, deposits, or pours over) ethanol 16 to wet solidscomponents 80 to increase the ethanol concentration of wet solidscomponents 80. Although ethanol distribution system 84 is illustrated asa series of spray nozzles, other means of applying ethanol 16 may beused. For example, ethanol 16 may be poured over wet solids components80. Wet solids components 80 will remain generally unperturbed by theapplication of ethanol 16. Once wet solids components 80 have beenwashed with ethanol 16, liquid 86 (e.g., a mixture of water and ethanol)from wet solids components 80 may be collected by a liquid collection88, such as a tank or collection tray. Co-products (e.g., zein andxanthophylls) may be extracted from liquid 86, and liquid 86 collectedby liquid collection 88 may be directed into distillation system 42 forfurther processing.

Wet solids components 80 washed with ethanol 16 may be transformed intowet solids components 90, which contain an increased concentration ofethanol 16 to water as compared to the initial wet solids components 80.Less energy may be required by a desolventizer 40 to dry (i.e.,desolventize) wet solids components 90 (e.g., after ethanol washing)than would be required by desolventizer 40 to dry (i.e., desolventize)wet solids components 80 (e.g., before ethanol washing). The reductionin energy required to desolventize/dry wet solids components 90 toproduce meal 18 may be due at least in part to the fact that wet solidscomponents 90 contain an increased concentration of ethanol 16 to wateras compared to wet solids components 80.

FIG. 15 is an exemplary graphical representation 92 of energy for dryingwet solids as it relates to the amount of ethanol present in the liquidportion of those wet solids. The horizontal axis in FIG. 15 representsthe volume of ethanol present in the liquid portion of the wet solids asa percent of the total liquid volume portion of the wet solids. Thevertical axis in FIG. 15 represents the amount of energy that it wouldtake to dry (e.g., by vaporization) all liquid from wet solids. Thegraphical representation in FIG. 15 represents the relationship of theamount of energy to dry the solids within the liquid portion as theconcentration of ethanol changes in the liquid portion of the wetsolids. In a conventional drying process, the wet solids may contain noethanol and may require ε₀ amount of energy to remove the liquid fromwet solids. By processing the wet solids to contain 20% by volume ofethanol, the amount of energy required to remove the liquid from wetsolids would decrease to ε₂₀ as depicted in FIG. 15. This trendcontinues as the ethanol concentration is increased, as seen when theethanol concentration is increased to 90% by volume and the new amountof energy required to remove the liquid portion is drastically reducedto ε₉₀. The lowest amount of energy required to remove the liquid fromwet solids can be achieved when the liquid is 100% ethanol.

Returning to FIGS. 13 and 14, increasing the ethanol concentration ofwet solids components 90 decreases the amount of energy required to drywet solids components 90 at least partially because water has arelatively high boiling point, heat capacity, and enthalpy (heat) ofvaporization as compared to ethanol. A relatively high amount of energyis required to heat water to a temperature sufficient to vaporize thewater; a relatively low amount of energy is required to heat ethanol toa temperature sufficient to vaporize ethanol. For example, the boilingpoint of ethanol is approximately 173° F. at atmospheric pressure; theboiling point of water is approximately 212° F. at atmospheric pressure.The heat capacity of ethanol is approximately 0.58 BTU/lb-° F.; the heatcapacity of water is 1.0 BTU/lb-° F. The enthalpy (heat) of vaporizationof ethanol is approximately 362 BTU/lb; the enthalpy (heat) ofvaporization of water is approximately 980 BTU/lb. Ethanol may be heatedwith less energy input, reaching its boiling point at a lowertemperature, and once at the boiling point, vaporizes with less energyinput.

Increasing the ethanol concentration of wet solids components 90 helpsto decrease the amount of energy required by desolventizer 40 todry/desolventize wet solids components 90. FIGS. 13 and 14 include onestage of ethanol washing. FIGS. 16 and 17 are a block flow diagram and aprocess flow diagram of exemplary embodiments of solids processingsystem 34, comprising multiple ethanol wash stages. Separation process50 may separate a liquid component shown as liquid 62 (e.g., awater/ethanol mixture) from a solids component shown as wet solids 64(e.g., a certain amount of ethanol, a certain amount of water, syrup,particulate matter, and dissolved solids). Liquid 62 may be directedinto distillation process 46, which may produce ethanol 16.

Ethanol 94 from distillation system 42 may be directed into a firststage wash 96, which also receives wet solids 64 from separation process50. Wet solids 64 from separation process 50 are washed with ethanol 94to increase the ethanol concentration of wet solids 64. It should benoted that when reference is made to “ethanol” in the discussions of thewash process, the fluid used may, and in many cases will, be anethanol-containing fluid, such as a mixture of water and ethanol. Anyother suitable solvent (e.g., hexane) may also be used. The “wash” fluidwill generally have a higher concentration of ethanol (or other solvent)than the wet solids receiving the wash, displacing water in the wetsolids with ethanol (or other solvent).

First stage wash 96 is configured to mix wet solids 64 with ethanol 94.Ethanol-washed solids 98 from first stage wash 96 may be directed into afirst stage separation 100, which separates first stage solids 102 fromfirst stage liquid 104. First stage liquid 104 may consist of awater/ethanol mixture, which may be directed back to distillation system42 for further processing. First stage liquid 104 washes away a certainamount of the water from wet solids 64. First stage solids 102 outputfrom first stage separation 100 will have a higher ethanol concentrationthan wet solids 64 input into first stage wash 96.

A second stream of ethanol 106 may be directed into a second stage wash108, which also receives first stage solids 102 from first stageseparation 100. First stage solids 102 from first stage separation 100may be washed with ethanol 106 to further increase the ethanolconcentration of first stage solids 102. Second stage wash 108 may beconfigured to mix first stage solids 102 with ethanol 106. Ethanol 106may be received from distillation system 42 or may be received fromother processes within biorefinery 10.

Ethanol-washed solids 110 from second stage wash 108 may be directedinto a second stage separation 112, which may separate second stagesolids 114 from second stage liquid 116. Second stage liquid 116 mayconsist of a water/ethanol mixture, which may be directed back to firststage wash 96. Second stage liquid 116 may supplement or replace ethanol94 from distillation system 42 to wash wet solids 64 in first stage wash96. Second stage liquid 116 washes away a certain amount of the waterfrom first stage solids 102. Second stage solids 114 output from secondstage separation 112 will have a higher ethanol concentration than firststage solids 102 input into second stage wash 108.

The ethanol wash cycles (e.g., washing and separating) may be repeatedmultiple times. A last stream of ethanol 118 may be directed into afinal stage wash 120, which also receives the previous stage solids froma previous stage separator. The previous stage solids may be washed withethanol 118 to further increase the ethanol concentration of theprevious stage solids. Final stage wash 120 may be configured to mix theprevious stage solids with ethanol 118. Ethanol 118 may be received fromdistillation system 42 or may be received from other processes withinbiorefinery 10.

Ethanol-washed solids 122 from final stage wash 120 may be directed intoa final stage separation 124, which may separate final stage solids 126from final stage liquid 128. Final stage liquid 128 will consist of awater/ethanol mixture, which may be directed back to the previous stagewash. Final stage liquid 128 may wash away a certain amount of the waterfrom the previous stage solids. Final stage solids 126 output from finalstage separation 124 will have a higher ethanol concentration than theprevious stage solids input into final stage wash 120.

Final stage solids 126 may then be directed into an evaporation stage130, in which the remaining liquid may be evaporated from final stagesolids 126, leaving dry or substantially dry meal 18. Ethanol vapor 132recovered from evaporation stage 130 may be condensed by a condenser 134and added to the final stage ethanol 118 in the final stage ethanol washcycle, as shown by line 136. In order to effect the condensation ofethanol vapor 132 from evaporation stage 130, a heat exchanger may beused to recover waste heat from any available source, and direct theheat into evaporation stage 130.

FIG. 17 is substantially similar to FIG. 16 with additional wash stagesillustrated. A third stream of ethanol 138 may be directed into a thirdstage wash 140, which also receives second stage solids 114 from secondstage separation 112. Second stage solids 114 from second stageseparation 112 may be washed with ethanol 138 to further increase theethanol concentration of second stage solids 114. Third stage wash 140may be configured to mix second stage solids 114 with ethanol 138.Ethanol 138 may be received from distillation system 42 or may bereceived from other processes within biorefinery 10.

Ethanol-washed solids 142 from third stage wash 140 may be directed intoa third stage separation 144, which may separate third stage solids 146from third stage liquid 148. Third stage liquid 148 may consist of awater/ethanol mixture, which may be directed back to second stage wash108. Third stage liquid 148 may supplement or replace ethanol 106 fromdistillation system 42 to wash first stage solids 102 in second stagewash 108. Third stage liquid 148 washes away a certain amount of thewater from second stage solids 114. Third stage solids 146 output fromthird stage separation 144 will have a higher ethanol concentration thansecond stage solids 114 input into third stage wash 140.

This process continues with a fourth stream of ethanol 150 being used bya next-to-final stage wash 152 to generate ethanol-washed solids 154,which may be separated by a next-to-final stage separation 156. Similarto the other wash stages, solids 158 from next-to-final stage separation156 may be directed into final stage wash 120; liquid from next-to-finalstage separation 156 may be directed to the previous wash stage.

The ethanol wash stages of FIGS. 16 and 17 may be repeated multipletimes such that the wet solids contain a low concentration of water anda high concentration of ethanol. The number of ethanol wash stages maybe chosen to achieve a particular concentration of ethanol in theresultant wet solids prior to drying. The concentration of the resultantwet solids prior to drying may be selectively adjusted. In each ethanolwash stage, the washes receive a quantity of ethanol wash containing ahigher ethanol concentration than the concentration present in the wetsolids. For each ethanol wash stage, a water/ethanol mixture may bereceived from a subsequent ethanol wash stage as an ethanol wash source.The water/ethanol mixture from a subsequent ethanol wash stage may besuitable for a previous ethanol wash stage because the water/ethanolmixture from the subsequent ethanol wash stage may generally containmore ethanol than the wet solids of the previous ethanol wash stage.Using ethanol from a subsequent ethanol wash stage allows the samestream of ethanol 94 brought into the initial ethanol wash stage to beused over and over again until the final ethanol wash stage. If enoughethanol wash stages are used, the composition of the resulting wetsolids will have an ethanol concentration approximately equal to theethanol concentration of ethanol used in the initial ethanol wash stage.After the multiple ethanol wash stages, the resultant final stage solids126 contain a liquid component with a higher concentration of ethanolthan wet solids 64 from separation process 50. In certain embodiments,ethanol stream 118 may be the only stream of ethanol used; ethanolstreams 94, 106, 138, and 150 may be used as make-up ethanol, toselectively control the concentration of ethanol in the other washstages, or may be omitted.

Returning to FIG. 15, to minimize the energy to dry meal 18, the ethanolconcentration of the resultant final stage solids 126 may be at or abovethe azeotropic ratio for water and ethanol (e.g., point A), which isapproximately 96% ethanol-to-water. At concentration levels at or abovethe azeotropic ratio, ethanol in wet solids will vaporize atsubstantially the same rate as the remaining water in the wet solids,leaving meal 18 while using the least amount of energy for drying. Witha ratio of ethanol-to-water below the azeotropic ratio, drying of wetsolids will be less efficient than when the ratio is at or above theazeotropic ratio. The process may bring the ethanol content of the wetsolids to any point along the concentration line with consequentbenefits to drying. In an effort to achieve certain benefits, the wetsolids will be brought to an ethanol concentration above the azeotropicratio.

Returning now to FIGS. 16 and 17, evaporation stage 130 may employ adryer for drying the resultant final stage solids 126, otherwisereferred to as wet cake. The drying process may expose meal 18 totemperatures just high enough to vaporize ethanol vapor 132 from meal18. Meal 18 may be altered and change color when exposed to hightemperatures. By limiting the temperature that final stage solids 126experience by using a low-energy drying process, the possibility ofaltering the meal 18 during evaporation stage 130 may be substantiallyreduced. Because final stage solids 126 may be dried at much lowertemperatures and with less energy input than in conventional processes,a large volume of air may not be required during evaporation stage 130.Because a lower volume of air may be used in evaporation stage 130 forlow-energy drying, the concentration of liquid in the resulting ethanolvapor 132 may be relatively high. Ethanol vapor 132 may also becondensed and re-used within biorefinery 10, reducing emissions frombiorefinery 10. Because water used in evaporation stage 130 may bere-circulated, more of the water initially injected into thesaccharification (if used) and fermentation processes of biorefinery 10may be sent back to distillation system 42, where it may be captured andre-used, significantly reducing the overall water consumption ofbiorefinery 10. The specific equipment of FIGS. 16 and 17 are merelyillustrative. Other specific equipment and processes may be used toimplement multiple ethanol wash stages to increase the ethanolconcentration of wet solids for the purpose of reducing the energyrequired to dry the wet solids.

Each stage of the solids processing (including steps in thewash/separation process) may be conducted on a single apparatus or (asindicated in FIGS. 16-18, for example) may be conducted on separateapparatus of the same type or including different types of apparatus(e.g., a filter belt system, separator, centrifuge, decanter, etc.);different stages of the processing of the solids component may beconducted on the same or on different/separate apparatus. In theprocessing of the wet solids (e.g. wet cake), additional operations tothe wash/separation process, including operations such as soaking,re-mixing, slurrying, or other processing of the solids component may beconducted in various sequences, before, during or after washing andseparating operations.

According to an exemplary embodiment, at least a portion of the solidsprocessing can be conducted on a filter belt system shown as includingfilter belt 162 (see, e.g., FIGS. 18 through 24). The filter belt systemmay include one or more belts (e.g., for conveying material), some ofwhich may be comprised of a filter media (e.g., to allow the filtrationof material on and through the belt), bulk handling systems for loadingand unloading the material into and from the system, controls and otherinstrumentation. The filter belt system may be segmented into stages orchambers (some of which may be configured to operate at differentialpressure, including vacuum or positive pressure). According to otherembodiments, other combinations of systems may be used for solidsprocessing of the solids component (e.g., wet solids or wet cake).

FIGS. 18A and 18B are cross-sectional views of an exemplary embodimentof an ethanol wash process 160 capable of implementing multiple ethanolwash stages. Ethanol wash process 160 comprises an apparatus shown as afilter belt 162 conveyed by a pair of rollers 164, 166. Rollers 164, 166are configured to rotate in a clockwise fashion, as shown by arrow 168,causing filter belt 162 to move in a left-to-right direction from thetop of roller 164 to the top of roller 166, as shown by arrow 170, andin a right-to-left direction from the bottom of roller 166 to the bottomof roller 164, as shown by arrow 172. The specific relative movement offilter belt 162 and rollers 164, 166 may vary among specificimplementations.

Wet solids 64 may be loaded onto the top of filter belt 162 and may movein a left-to-right direction. The left-hand end of filter belt 162 maybe referred to as the upstream end; the right-hand end of filter belt162 may be referred to as the downstream end. Ethanol wash process 160utilizes a counterflow ethanol wash process. Ethanol may flow throughethanol wash process 160 from the downstream end of filter belt 162 tothe upstream end of filter belt 162; wet solids 64 may flow throughethanol wash process 160 from the upstream end of filter belt 162 to thedownstream end of filter belt 162. The ethanol used for ethanol washprocess 160 generally flows in a direction opposite from the flow of wetsolids 64. The ethanol used for ethanol wash process 160 mayalternatively flow in the same direction as wet solids 64.

Ethanol may be introduced into ethanol wash process 160 toward thedownstream end of filter belt 162. A first stream of ethanol 174 may beapplied to (e.g., poured over, sprayed onto, or deposited onto) wetsolids 64 by ethanol distribution system 84 above a first downstreamcollection vessel 176. A mixture of water and ethanol may be drawnthrough filter belt 162 by gravity and/or vacuum into collection vessel176 or the flow of the mixture of water and ethanol through filter belt162 and into collection vessel 176 may be facilitated by positivedifferential pressure above filter belt 162. The water/ethanol mixture178 from collection vessel 176 may then be combined with a second streamof ethanol 180, with the combination being applied to (e.g., pouredover, sprayed onto, or deposited onto) wet solids 64 by ethanoldistribution system 84 above a second downstream collection vessel 182,which is upstream of collection vessel 176. The first stream of ethanol174 may have a higher, lower, or substantially similar concentration ofethanol than the second stream of ethanol 180. In other embodiments, thesecond stream of ethanol 180 may not be combined with the water/ethanolmixture 178 from collection vessel 176, but rather only thewater/ethanol mixture 178 may be applied to wet solids 64. A mixture ofwater and ethanol may be drawn through filter belt 162 by gravity and/orvacuum into collection vessel 182 or the flow of the mixture of waterand ethanol through filter belt 162 and into collection vessel 182 maybe facilitated by positive differential pressure above filter belt 162.The water/ethanol mixture 184 from collection vessel 182 may then beapplied to (e.g., poured over, sprayed onto, or deposited onto) wetsolids 64 by ethanol distribution system 84 above a third downstreamcollection vessel 186, which is upstream of collection vessel 182.

Water/ethanol mixture 188 from collection vessel 186 may be directedtoward other upstream ethanol distribution systems 84. Ultimately,water/ethanol mixture 190 may be applied to (e.g., poured over, sprayedonto, or deposited onto) wet solids 64 by ethanol distribution system 84above a first upstream collection vessel 192. Water/ethanol mixture 194from collection vessel 192 may be directed back to distillation system42 to recapture some of the ethanol. A second upstream collection vessel196 upstream of collection vessel 192 may collect water/ethanol mixture198, which may also be directed back to distillation system 42 torecapture some of the ethanol. A final downstream collection vessel 200downstream of collection vessel 176 may collect water/ethanol mixture200, which may also be directed back to distillation system 42 torecapture some of the ethanol. Collection vessel 200 may also act as anevaporation stage, whereby the last remaining water/ethanol mixture 202may be removed or joined with the water/ethanol mixture 178 fromcollection vessel 176. A separate drying process, such as evaporationstage 130 of FIGS. 16 and 17 and/or desolventizer 40 of FIGS. 13 and 14may also be used downstream of ethanol wash process 160.

More or less pure ethanol may be applied to wash the wet solids at thevarious locations along the filter belt 162. Such concentrations, alongwith the flow rates of the wash fluid and the speed of the filter belt162, may serve to control the rate of displacement of water in the wetsolids by ethanol. Such factors may regulate the relative difference inethanol content at each wash stage, as well as the ultimate ethanolcontent of the wet solids just before final drying.

FIGS. 19 through 23 are cross-sectional views at various locations alongfilter belt 162 of FIGS. 18A and 18B. For example, FIG. 19 is across-sectional view of filter belt 162 of FIGS. 18A and 18B upstream ofthe location where wet solids 64 are placed onto filter belt 162 shownby arrow 204 in FIGS. 18A and 18B. Although any filter belt technologymay be employed, filter belt 162 may have a substantially perforated orporous structure such that a liquid component of wet solids 64 on filterbelt 162 may be drawn through filter belt 162 or the flow of the mixtureof water and ethanol through filter belt 162 may be facilitated bypositive differential pressure above filter belt 162. Filter belt 162may also include a collection tray 206, which may facilitate thecollection of water/ethanol mixtures collected through filter belt 162.Collection tray 206 may include a collection opening 208, through whichwater/ethanol mixtures may be collected into collection vessels. FIG. 20is a cross-sectional view of filter belt 162 of FIGS. 18A and 18B at alocation where wet solids 64 are placed onto filter belt 162 shown byarrow 210 of FIGS. 18A and 18B. A vacuum or gravity beneath filter belt162 may draw a water/ethanol mixture 212 from wet solids 64 ontocollection tray 206 and into collection vessel 196, as shown by arrows214. FIG. 21 is a cross-sectional view of filter belt 162 of FIGS. 18Aand 18B upstream of ethanol distribution system 84 shown by arrow 216.At this point on filter belt 162, wet solids 64 will contain a certainconcentration of ethanol. FIG. 22A is a cross-sectional view of filterbelt 162 of FIGS. 18A and 18B at a location near ethanol distributionsystem 84 shown by arrow 218. At this point, ethanol is introduced intowet solids 64 by ethanol distribution system 84, transforming wet solids64 into a mixture of liquids 220 (e.g., a water/ethanol mixture) andsolids 222. A vacuum or gravity beneath filter belt 162 may draw awater/ethanol mixture 212 from wet solids 64 onto collection tray 206and into a collection vessel, as shown by arrows 214. FIG. 22B is across-sectional view of filter belt 162 of FIGS. 18A and 18B at alocation near ethanol distribution system 84 shown by arrow 218. Apressure chamber 223 may be used to create a differential pressurebetween the top and bottom of filter belt 162. Pressure may be appliedwithin pressure chamber 223 to facilitate washing by effectivelyfacilitating the flow of the ethanol through wet solids 64. Wet solids64 downstream of location 218 of filter belt 162 will have a higherethanol concentration than wet solids 64 upstream of location 218 offilter belt 162. FIG. 23 is a cross-sectional view of filter belt 162 ofFIGS. 18A and 18B at a location near collection vessel 200, as shown byarrow 224. Collection vessel 200 may be used as an evaporation stage.Heated gas 226 may be applied to wet solids 64 above filter belt 162. Avacuum or gravity beneath filter belt 162 may draw heated gas 226through wet solids 64 and an ethanol vapor 228 may be collected andfurther processed to recover ethanol and other desirable componentspresent in ethanol vapor 228.

FIG. 24 is a perspective view of another exemplary embodiment of ethanolwash process 160. Wet solids 64 may be placed on filter belt 162 at anupstream location with meal 18 exiting at a downstream location offilter belt 162. An initial collection vessel 196 may collectwater/ethanol mixture 198 without washing, which may be directed back todistillation pre-treatment process 44. The first stream of ethanol 174may be applied to wet solids 64 above collection vessel 176. A mixtureof water and ethanol may be drawn through filter belt 162 by gravityand/or vacuum into collection vessel 176 or the flow of the mixture ofwater and ethanol through filter belt 162 and into collection vessel 176may be facilitated by positive differential pressure above filter belt162. The water/ethanol mixture from collection vessel 176 may bedirected into a first conditioning process 230, which may filter andcondition the water/ethanol mixture. A portion of the ethanol/watermixture may be directed to co-product processing, as shown by arrow 232;filtered/conditioned ethanol from conditioning process 230 may beapplied to wet solids 64 above collection vessel 182.

A mixture of water and ethanol may be drawn through filter belt 162 bygravity and/or vacuum into collection vessel 182 or the flow of themixture of water and ethanol through filter belt 162 and into collectionvessel 182 may be facilitated by positive differential pressure abovefilter belt 162. The water/ethanol mixture from collection vessel 182may be directed into a second conditioning process 234, which may filterand condition the water/ethanol mixture. A portion of the ethanol/watermixture may be directed to co-product processing, as shown by arrow 236;filtered/conditioned ethanol from conditioning process 234 may beapplied to wet solids 64 above previous upstream collection vessels.Ultimately, a mixture of water and ethanol may be drawn through filterbelt 162 by gravity and/or vacuum into collection vessel 192 or the flowof the mixture of water and ethanol through filter belt 162 and intocollection vessel 192 may be facilitated by positive differentialpressure above filter belt 162. The water/ethanol mixture 194 fromcollection vessel 192 may be directed to distillation pre-treatmentprocess 44.

In certain embodiments, the apparatus comprising a filter belt mayinclude two or more such belts. For example, a first belt may be usedfor a first stage of washing with ethanol (or another solvent), whilefurther filter belts may be used for subsequent stages. The materialconveyed with the belts may be transferred from one belt to the other asthe process progresses. Some embodiments may include intermediateequipment between filter belts, such as mixers for creating a slurrywith the solvent or solvent mixture, centrifuges or other separators forperforming some degree of moisture removal, and so forth. The filterbelts themselves may be of any suitable type, including arrangements inwhich a semi-permeable belt serves as a substrate used to receive thesolids component, and apparatuses with multiple layers of belts, supportstructures, and so forth.

FIG. 25 is a flow chart of an exemplary embodiment of solids processingsystem 34. Separation process 50 may be performed to separate a liquidcomponent shown as liquid 62 (e.g., a water/ethanol mixture) from asolids component shown as wet solids 64 (e.g., a certain amount ofethanol, a certain amount of water, syrup, particulate matter, anddissolved solids). Wet solids 64 may then be washed with ethanol (e.g.,wash process 52). For example, a solvent (e.g., ethanol) may be added towet solids 64, as shown by block 238. Once ethanol has been added to wetsolids 64, wet solids 64 may be separated to remove a mixture of waterand ethanol from wet solids 64 (e.g., separation process 38). Wet solids64 will contain a higher concentration of ethanol than before washprocess 52 and separation process 38. Wet solids 64 may then bedesolventized to remove remaining liquids from wet solids 64 to producemeal 18 (e.g., desolventizing process 40). In each of separation process38 and desolventizing process 40, liquid and vapor may be captured, asshown by block 240. The liquid and vapor may be distilled and used as asource of ethanol in wash process 52, as shown by block 242. The liquidand vapor may be re-used by wash process 52.

FIG. 26 is a flow chart of an exemplary embodiment of multiple solidsprocessing system 34 stages. Separation process 50 may be performed toseparate a liquid component shown as comprising liquid 62 (e.g., awater/ethanol mixture) from a solids component shown as comprising wetsolids 64 (e.g., a certain amount of ethanol, a certain amount of water,syrup, particulate matter, and dissolved solids). Wet solids 64 may thenbe washed with ethanol (e.g., wash process 52). Once ethanol has beenadded to wet solids 64, wet solids 64 may be separated to remove amixture of water and ethanol from wet solids 64 (e.g., separationprocess 38). Wet solids 64 will contain a higher concentration ofethanol than before wash process 52 and separation process 38.Subsequent ethanol wash stages may be used to further increase theethanol concentration of wet solids 64 before desolventizing process 40.For example, wet solids 64 may be washed again with concentrated ethanol(e.g., wash process 52). For example, a solvent (e.g., ethanol) mayagain be added to wet solids 64, as shown by block 238. Once ethanol hasagain been added to wet solids 64, wet solids 64 may be separated againto remove a mixture of water and ethanol from wet solids 64 (e.g.,separation process 38). Wet solids 64 may contain an even higherconcentration of ethanol than before ethanol wash processes 52 andseparation processes 38. Wet solids 64 may then be desolventized toremove remaining liquids from wet solids 64 to produce meal 18 (e.g.,desolventizing process 40). In each of separation processes 38 anddesolventizing process 40, liquid and vapor may be captured, as shown byblocks 240. The liquid and vapor may be re-distilled and used in otherprocesses internal and/or external to biorefinery 10, as shown by block242. The liquid and vapor may be re-used by previous wash processes 52.

Various processes upstream of solids processing system 34 may also leadto significant tangible benefits. For example, FIG. 27 is a process flowdiagram of an exemplary embodiment of fractionation process 78.Exemplary processes are described in U.S. Patent Application PublicationNo. 2005/0233030, U.S. Patent Application Publication No. 2007/0037267,U.S. Patent Application Publication No. 2007/0178567, and U.S. PatentApplication Publication No. 2007/0202214, each of which is incorporatedby reference. Corn 12 may initially be processed into individual cornkernels 244, which may be fractionated within fractionation process 78.Each corn kernel 244 may be comprised of endosperm 246, fiber 248, germ250, and a tip cap 252. Endosperm 246 comprises most of the starches andproteins available in corn kernel 244 and is used in fermentationprocess 28 to generate ethanol 16. Endosperm 246 represents thefermentable solids 58 of corn kernel 244; germ and fiber represent thenon-fermentable solids 56 of corn kernel 244, which may be withheld fromfermentation process 28. Endosperm 246 comprises approximately 80-85% ofcorn kernel 244 by mass, germ 250 comprises approximately 10-15% of cornkernel 244 by mass, and fiber 248 comprises approximately 5-10% of cornkernel 244 by mass.

Fractionation process 78 prepares corn kernels 244 for saccharificationand fermentation in saccharification process 26 and fermentation process28. Fractionation process 78 reduces corn kernel 244 to make starchesand proteins within corn kernel 244 more readily available forsaccharification and fermentation. For example, corn kernel 244 mayfirst be fractionated into its component parts, such as germ 250, fiber248, and endosperm 246. Tempered whole corn may be fed into a primaryseparation stage 254, which substantially separates corn kernel 244 intocomponents (e.g., fractions) of endosperm germ 250, fiber 248, andendosperm 246. Primary separation stage 254 may also separate out fiber248 (e.g., bran) and flour (e.g., comprising a fine powder of endosperm246) and may direct the remaining components of corn kernel 244 into asecondary separation stage 256. Fiber 248 from primary separation stage254 may be processed through a secondary starch recovery process. Thesecondary starch recovery process may include a milling stage, aseparation stage, and a mechanical fiber dusting stage. The millingstage may utilize a pin mill, a hammer mill, a roller mill, or othersuitable mill technology.

Secondary separation stage 256 may further remove germ 250 fromendosperm 246. Germ 250 from secondary separation stage 256 may passthrough a secondary refining (or purification) process, which mayinclude a milling stage and a separation stage. The milling stage mayutilize a roller mill. Grits (e.g., endosperm 246) from the secondaryrefining process may be passed to a mechanism for reducing their size,such as a hammer mill, prior to fermentation.

Fractionating corn kernel 244 to separate endosperm 246 (e.g.,fermentable solids) from germ 250 and fiber 248 (e.g., non-fermentablesolids) may provide several benefits to processes downstream offractionation process 78. For example, using primarily endosperm 246 insaccharification process 26 may enhance the efficiency ofsaccharification process 26 because non-fermentable solids 56 aregenerally not involved in saccharification process 26. The fact that thefermentation slurry from saccharification process 26 includes primarilyendosperm 246, water, and enzymes may also lead to fermentation process28 being more efficient because non-fermentable solids 56 are generallynot involved in fermentation process 28.

By fractionating corn kernel 244 prior to fermentation, the levels ofproteins (e.g., zein) may be increased. For example, removing germ 250and fiber 248 fractions prior to fermentation process 28 may concentrateproteins in the fermentation slurry delivered to fermentation process28. Proteins are generally isolated in endosperm 246 of corn kernel 244and fractionation of protein-enriched endosperm 246 results inconcentration of proteins in residuals from fermentation process 28.

Endosperm 246 from secondary separation stage 256 may be directed into amilling process, where endosperm 246 may be milled and reduced inparticle size to prepare the ground endosperm for saccharificationprocess 26 and fermentation process 28. Endosperm 246 may be reducedusing any suitable method, including grinding, to make starches withinendosperm 246 more readily available for saccharification process 26 andfermentation process 28. The specific equipment used to grind endosperm246 may include, for example, a ball mill, a roller mill, a hammer mill,or any other type of mill capable of grinding endosperm 246 for thepurpose of particle size reduction. The use of emulsion technology,sonic pulsation, rotary pulsation, and other particle size reductionmethods may be utilized to increase the surface area of endosperm 246,while also raising the effectiveness of flowing the liquefied media(e.g., decreased viscosity). The ground endosperm 246 may be referred toas being or including “raw starch.” Grinding endosperm 246 exposes moresurface area of endosperm 246 and may facilitate saccharificationprocess 26 and fermentation process 28.

Ground endosperm 246 from fractionation process 78 may be directed intosaccharification process 26, in which starches within ground endosperm246 may be converted into sugars that may be fermented in fermentationprocess 28. FIG. 28 is a block flow diagram of an exemplary embodimentof saccharification process 26. Endosperm 246 may be combined in areaction tank 258 with a saccharifying enzyme composition 260, water262, and heat 264 to facilitate the conversion. The saccharifying enzymecomposition 260 may include an amylase, such as an alpha amylase (e.g.,an acid fungal amylase). The saccharifying enzyme composition 260 mayalso include glucoamylase. The saccharifying enzyme composition 260 mayalso include acid fungal amylase for hydrolyzing raw starch withinground endosperm 246.

The term “saccharifying” refers to the process of converting starcheswithin ground endosperm 246 into smaller polysaccharides and eventuallyto monosaccharides, such as glucose. Conventional saccharificationmethods use liquefaction of gelatinized starch to create solubledextrinized substrates that hydrolyze into glucose. Saccharificationprocess 26 may be conducted without cooking. The phrase “withoutcooking” generally refers to a process for converting starch to sugarswithout heat treatment for gelatinization and dextrinization of starcheswithin ground endosperm 246. “Without cooking” (e.g., a “raw starch”process) refers to maintaining a temperature below starch gelatinizationtemperatures of ground endosperm 246 such that saccharification occursdirectly from the raw native insoluble starch to soluble glucose, whilebypassing conventional starch gelatinization conditions. Starchgelatinization temperatures are typically in a range of 57-93° C.,depending on the starch source and polymer type. Saccharificationprocess 26 may be conducted in a temperature range of approximately25-40° C. Exemplary processes are described in U.S. Patent ApplicationPublication No. 2004/0234649, U.S. Patent Application Publication No.2005/0233030, U.S. Patent Application Publication No. 2005/0239181, U.S.Patent Application Publication No. 2007/0037267, U.S. Patent ApplicationPublication No. 2007/0178567, U.S. Patent Application Publication No.2007/0196907, and U.S. Patent Application Publication No. 2007/0202214,each of which is incorporated by reference.

Saccharification process 26 may include mixing ground endosperm 246 witha liquid (e.g., water 262), which may form a slurry or suspension, andadding a saccharifying enzyme composition 260 to the slurry. Theaddition of the saccharifying enzyme composition 260 may occur before orduring mixing of ground endosperm 246 with water 262. Saccharificationprocess 26 may convert raw or native starch to sugars at a faster rateas compared to conventional saccharification methods that utilizecooking. The percentage of ground endosperm 246 to water 262 may behigher as compared to conventional saccharification methods that utilizecooking because, unlike conventional processes, saccharifying groundendosperm 246 without cooking does not include gelatinization, whichincreases viscosity.

Saccharification process 26 may utilize any enzyme sources suitable forsaccharifying starches within ground endosperm 246 to producefermentable sugars without cooking. The saccharifying enzyme composition260 may include an amylase, such as an alpha amylase (e.g., an acidfungal amylase) or a glucoamylase. The initial pH of saccharificationprocess 26 may be adjusted by the addition of, for example, ammonia,sulfuric acid, phosphoric acid, or process waters (e.g., stillage orbackset, evaporator condensate or distillate, side stripper bottoms).

The ability of saccharification process 26 to convert starches withinground endosperm 246 to produce fermentable sugars without cookingground endosperm 246 may provide several tangible benefits. For example,meal 18 that is ultimately produced by biorefinery 10 may generally beof higher quality because ground endosperm 246 is not cooked. Meal 18produced by biorefinery 10 may include elevated levels of protein ascompared to conventional DDG 54. Meal 18 produced by biorefinery 10 mayalso include elevated levels of B vitamins, vitamin C, vitamin E, folicacid, amino acids (e.g., lysine), and/or vitamin A as compared toconventional DDG 54. Meal 18 produced by biorefinery 10 may also haveimproved physical characteristics, such as decreased caking orcompaction and increased ability to flow.

Fermentation slurry 266 from saccharification process 26 may be directedinto fermentation process 28, in which the sugars within thefermentation slurry 266 are fermented to produce ethanol 16. FIG. 29 isa block flow diagram of an exemplary embodiment of fermentation process28. Exemplary processes are described in U.S. Patent ApplicationPublication No. 2004/0234649, U.S. Patent Application Publication No.2005/0233030, U.S. Patent Application Publication No. 2005/0239181, U.S.Patent Application Publication No. 2007/0037267, U.S. Patent ApplicationPublication No. 2007/0178567, U.S. Patent Application Publication No.2007/0196907, and U.S. Patent Application Publication No. 2007/0202214,each of which is incorporated by reference. Fermentation slurry 266 maybe combined in fermentation tank(s) 268 with enzymes 270 and yeast 272to facilitate fermentation. Fermentation process 28 may be facilitatedby mixing the yeast 272 with fermentation slurry 266 under conditionssuitable for growth of the yeast 272 and production of ethanol 16.Fermentation slurry 266 contains sugars that have been converted fromstarches without cooking.

Any of a variety of yeasts 272 may be utilized as the yeast starter infermentation process 28. Yeast 272 may be selected to provide rapidgrowth and fermentation rates in the presence of high temperature andhigh ethanol levels. The amount of yeast starter utilized is selected toeffectively produce a commercially significant quantity of ethanol 16within a suitable time from (e.g., less than 72 or 144 hours). Yeast 272may be added to fermentation slurry 266 by any of a variety of methodsknown for adding yeast 272 to fermentation processes. Yeast starter maybe added as a dry batch, or by conditioning/propagating. Yeast startermay also be added as a single inoculation.

Fermentation process 28 may be conducted as either a continuous processor a batch process. As a continuous process, fermentation slurry 266from saccharification process 26 may be moved (e.g., pumped) through aseries of vessels (e.g., tanks) to provide a sufficient duration forfermentation process 28. Fermentation process 28 may also includemultiple stages of vessels. For example, fermentation slurry 266 fromsaccharification process 26 may be fed into the top of a first vesselstage, partially fermented slurry drawn out of the bottom of the firstvessel stage may be fed into the top of a second vessel stage, andpartially fermented slurry drawn out of the bottom of the second vesselstage may be fed into the top of a third vessel stage. As a batchprocess, fermentation slurry 266 may be directed into a vessel, wherethe fermentation cycle may be completed before the vessel is emptied.

Output from fermentation process 28 may include the fermentation productshown as beer 32. Ethanol 16 may be recovered from liquids in beer 32,meal 18 may be recovered from solids in beer 32, and other variousby-products (e.g., proteins and corn syrup) may be separated from beer32. Fermentation process 28 may generate a relatively large amount ofcarbon dioxide (CO₂) and other gases. A system may be installed atbiorefinery 10 to capture, re-use, and/or otherwise dispose (e.g., viasequestration) of the gases.

Fermentation product 32 (e.g., beer) may be separated by separationprocess 50 into a liquid component (e.g., liquid 62) and a solidscomponent (e.g., wet solids 64). FIG. 30 illustrates exemplaryembodiments of separation process 50. Liquid 62 may be directed intodistillation system 42, where ethanol 16 may be produced. By directingprimarily liquid 62 to distillation system 42, equipment of distillationsystem 42 may be less susceptible to fouling, which is usually caused bysolids present when fermented beer is distilled directly, such as inconventional methods. Because liquid 62 has substantially fewer solids,occurrences of fouling may be substantially reduced. With a reducedsusceptibility to fouling, complicated anti-fouling provisions may beunnecessary, reducing the complexity and cost of distillation system 42.Because liquid 62 is substantially free of solids components, heatenergy applied to distillation system 42 may only have to heat thoseminimal solids dissolved in liquid 62, reducing heat energy requirementsof distillation system 42 compared to conventional distillation systems,which must heat both the solids and liquid components of fermented beer.

Wet solids 64 may be directed into solids processing system 34, whereethanol (or other solvents) may be added to wet solids 64 to decreasethe boiling point, heat capacity, and enthalpy (heat) of vaporization ofwet solids 64. The ethanol concentration of wet solids 64 fromseparation process 50 may generally be determined by fermentationprocess 28, and may typically fall within a range of 10-20% by volume,although ethanol concentrations above and below this range may also beused. A substantial portion of water will be removed from beer 32 asliquid 62 and, as such, the boiling point, heat capacity, and enthalpy(heat) of vaporization of wet solids 64 may be reduced downstream ofseparation process 50 as compared to beer 32 upstream of separationprocess 50. The amount of energy required to dry/desolventize wet solids64 (i.e., having a lower boiling point, heat capacity, and enthalpy(heat) of vaporization) may be substantially reduced compared toconventional deliquification/drying systems, which must deliquify anddry stillage containing higher concentrations of water (i.e., having ahigher boiling point, heat capacity, and enthalpy (heat) ofvaporization).

By separating liquid components (e.g., liquid 62) from the solidscomponents (e.g., wet solids 64) of beer 32 prior to distillation system42, the favorable physical characteristics of ethanol may be exploited(particularly the low boiling point, low specific heat, and low enthalpy(heat) of vaporization of ethanol) to evaporate liquid matter from wetsolids 64, producing meal 18. Rather than drying stillage that has beenprocessed in a distillation system and contains little to no ethanol,ethanol-containing wet solids 64 may be dried using lower amounts ofenergy as compared to conventional methods. Separation process 50 may beperformed by any suitable separation means including, but not limitedto, a disk-type centrifuge 274, a decanter centrifuge 276, a hydroclone278, a sedimentation tank 280, or a filter press 282. Indeed, any typeof separator capable of separating liquid 62 from wet solids 64 may beused.

Meal 18 produced by biorefinery 10 may also be reconstituted into feedat a desired composition to differentiate the product for variousmarkets. For example, some protein and any extracted biochemicals orother bioproducts may be re-applied to the resulting meal to constitutethe desired end product. Levels of protein and other amino acids couldbe selectively adjusted. For example, proteins, fats, syrup, oils,lutein, lysine, zein, and other bioproducts and biochemicals may beselectively combined with the meal. According to preferred embodiment,processing of the meal may take place at temperatures that avoiddegradation of the meal itself. The use of such reduced temperatures atall stages of processing (through the plant) results in a meal that isof a different quality than conventional DDG (i.e., resulting from aprocess employing “cooked” liquefaction). For example, maintaining theprocessing temperatures below about 150° C. is believed to produce aproduct that is quite distinct from conventionally processed DDG, andeven lower temperatures, on the order of 100° C. (or even lower, at 93°C., 180° F., or 130° F.) are particularly helpful in creating a uniquemeal.

Depending upon the processing, the meal may be referred to as “cornmeal” (particularly when corn is the feedstock), “distillers meal”,“distillers dried meal”, “dried distillers meal”, “protein-containingmeal”, and “corn distillers meal”, among others. When the solidscomponent is subject to the distillation process, the resulting productmay be different still, somewhat more akin to conventional DDG, althoughcertain benefits of the processing are nevertheless realized, such asthe reduction in energy utilization in the biorefinery.

The meal may also be further transformed for particular productcategories and markets. For example, the meal may be mechanicallypressed or extruded into pellets configured for packaging,transportation, durability, and digestibility. Such processing may bewell suited for producing animal feeds. Within this category of product,a number of varieties may be formulated including different ingredients,protein qualities, additives, sizes, and configurations.

While only certain features and embodiments of the invention have beenillustrated and described, many modifications and changes may occur tothose skilled in the art (e.g., variations in sizes, dimensions,structures, shapes and proportions of the various elements, values ofparameters (e.g., temperatures, pressures, etc.), mounting arrangements,use of materials, colors, orientations, etc.) without materiallydeparting from the novel teachings and advantages of the subject matterrecited in the claims. The order or sequence of any process or methodsteps may be varied or re-sequenced according to alternativeembodiments. It is, therefore, to be understood that the appended claimsare intended to cover all such modifications and changes as fall withinthe true spirit of the invention. Furthermore, in an effort to provide aconcise description of the exemplary embodiments, all features of anactual implementation may not have been described (i.e., those unrelatedto the presently contemplated best mode of carrying out the invention,or those unrelated to enabling the claimed invention). It should beappreciated that in the development of any such actual implementation,as in any engineering or design project, numerous implementationspecific decisions may be made. Such a development effort might becomplex and time consuming, but would nevertheless be a routineundertaking of design, fabrication, and manufacture for those ofordinary skill having the benefit of this disclosure, without undueexperimentation.

1. A method for processing a fermentation product of a fermentationprocess in a biorefinery that performs distillation of ethanol, thefermentation product comprising a liquid component and a solidscomponent, the method comprising the steps of: (a) preparing a cornfeedstock into a slurry containing fermentable matter; (b) saccharifyingand fermenting the slurry while maintaining the slurry at a temperaturebelow a starch gelatinization temperature to obtain a fermentationproduct, the fermentation product comprising a liquid component and asolids component; (c) applying a solvent to the solids component; and(d) drying the solids component.
 2. The method of claim 1 wherein theslurry is saccharified using enzymes.
 3. The method of claim 2 whereinthe slurry is saccharified using glucoamylase and acid fungal amylase.4. The method of claim 1 wherein steps (a)-(d) are performed withoutraising the temperature of the slurry and the solids component above atemperature of about 150° C.
 5. The method of claim 4 wherein steps(a)-(d) are performed without raising the temperature of the slurry andthe solids component above a temperature of about 93° C.
 6. The methodof claim 5 wherein steps (a)-(d) are performed without raising thetemperature of the slurry and the solids component above a temperatureof about 80° C.
 7. The method of claim 1 wherein the solvent compriseshexane.
 8. The method of claim 1 wherein the solvent comprises ethanol.9. The method of claim 8 wherein the solids component comprises amoisture content comprising an ethanol component and a water component,and wherein the composition of the solids component is altered bydecreasing the water component.
 10. The method of claim 9 wherein thecomposition of the solids component is altered by increasing the ethanolcomponent.
 11. The method of claim 9 comprising collecting liquid and/orgas from the solids component, and increasing ethanol content of theliquid and/or gas collected from the solids component to obtain a higherethanol-content liquid, and wherein the higher ethanol-content liquid isapplied to the solids component.
 12. The method of claim 11 wherein theliquid and/or gas is collected from the solids component by applicationof at least one of a positive pressure, a vacuum pressure, and heat tothe solids component.
 13. The method of claim 9 comprising performingstep (c) at least twice to drive the components of the moisture contenttowards the water/ethanol azeotropic point.
 14. The method of claim 13wherein performance of step (c) is stopped, and the solids component isdried prior to reaching the water/ethanol azeotropic point.
 15. Themethod of claim 9 comprising performing step (c) up to or beyond thewater/ethanol azeotropic point.
 16. The method of claim 15 comprisingperforming step (c) until the moisture content is substantially entirelyethanol.
 17. The method of claim 9 wherein the ethanol is produced bydistillation of the liquid component of the fermentation products. 18.The method of claim 1 comprising removing a portion of the solidscomponent bioproduct from the solids component prior to drying.
 19. Themethod of claim 1 wherein the solids component comprises meal.
 20. Themethod of claim 1 wherein the process produces distillers dried meal.